References to "developed lands" in the Natural Resources Inventory embrace three types of developments:
It is likely that a small portion of the "large urban and built-up areas" includes land that is not urbanized, such as a rural agricultural storage facility or food-processing plant that is larger than ten acres. But most of the large urban and built-up areas is urban and this number is the best one to use when discussing the amount of land in the U.S. that is urbanized.
The revised NRI report did not include data breaking developed land into these categories. On request, USDA provided these data to the Thoreau Institute and we have posted them in your choice of Excel or in tab-delimited text format.
The data reveal that only 72 percent of the developed land in the U.S. falls into the large urban and built-up areas category. This ranges from just 23 percent in North Dakota to 94 percent in New Jersey. These numbers should be compared with table one in the Natural Resources Inventory to see how much of each state is large urban and built up. Be sure to distinguish whether you are comparing large urban to all land or all land and water in each state.
In the 1997 inventory, large urban and built-up area represents just under 70 million acres. The land area of the United States -- including Alaska, which is not in the NRI data -- is 2,307 million acres (not including water). Census Bureau data indicate that only a tiny portion of Alaska -- around 100,000 acres -- is urbanized.
This means that the revised NRI data indicate that just 3.03 percent of the U.S., including Alaska, was urbanized in 1997. Considering that these lands house three-quarters of the population, that doesn't seem like very much.
If we leave Alaska out, large urban and built-up areas still cover less than 3.7 percent of the rest of country. Even the NRI summary report admits that urban and other developments are "not considered a threat to the Nation's food production overall."